Before she was a journalist, Elizabeth Arnold spent several seasons fishing salmon commercially in her home state of Alaska. In 1985, she began reporting for Juneau’s NPR member station KTOO, covering local environmental and political stories. From 1991 to 2006, she served as a political correspondent out of NPR’s headquarters in Washington, D.C., where she covered campaigns, Congress and the White House

Like it or not, your body is teeming with trillions of bugs — microbial cells, that is. Thinking about these bacteria and other microorganisms that you host both outside and inside your body might leave you feeling queasy, but they’re actually critical to maintaining your health, from your weight to your mood.

If you’ve ever pumped gas in the United States, you’ve seen the sticker: “This product may contain up to 10 percent ethanol by volume,” declares one at a Massachusetts Shell station. Since 2005, Washington has mandated that an increasing amount of ethanol be mixed into gasoline every year, encouraging refiners and retailers with cash incentives.

For decades, scientists have known that daylight is essential to human health. Back in 1948, the British Medical Journalpoked fun at a group of engineers who tried to convince doctors that artificial light was superior to sunlight.

For almost a decade, residents of some Pennsylvania counties have complained that the natural gas prospectors nearby have contaminated their water. Locals say that after the fracking for gas began, the water made them sick, that it turned brown, even that it became flammable.